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480
M
ASTOVSKA
ET AL
.
J
OURNAL OF
AOAC I
NTERNATIONAL
V
OL
. 98, N
O
. 2, 2015
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used to interpolate the analyte concentration.
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participants determined absolute recoveries of both PAHs and
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solution in ethyl acetate and reconstitution in isooctane and
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naphthalene, and & QDSKWKDOHQH KDG WR EH DERYH
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or could be obtained commercially from different vendors. The
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in different amounts of water in the silica thus potentially
different retention characteristics. Therefore, it is important
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optimum volume of the elution solvent to ensure adequate
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them to dryness.
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used instead of the sample. The concentrations of all analytes
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lowest calibration level standard. For naphthalene, levels below
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naphthalene in the sample) were still acceptable if the source of
contamination could not be eliminated, such as by selection of
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evaporation, etc.
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that were both supplied to them. The samples were spiked at
PAH concentrations equivalent to the second lowest calibration
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requirement established for the study) to test instrument
sensitivity and method precision. The shrimp matrix had to
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Two of the three samples were shrimp blank matrix already
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Quality Assurance
The method uses a mixture of isotopically labeled & 3$+
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lower concentration levels, a limited calibration curve (without
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calibration standard concentrations, and analyte concentrations,
the collaborators were also required to report ion ratios as a
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of the blank mussel and oyster matrixes were spiked with
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Data Reporting
Participants supplied PAH and & 3$+ VLJQDOV SHDN DUHDV
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conditions, evaporation equipment and conditions, and silica
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were asked to record all observations and any potential method
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preparation or contamination), and have all the results and